In a book series celebrating C. West Churchman, John P. van Gigch digests (and portends to extend) The Systems Approach and its Enemies.

On enemies …

4.1 A MATTER OF DEFINITIONS: ADVERSARIES VERSUS ENEMIES
I note the similarity/difference between the words ‘enemy’ and ‘adversary.’ Other authors use the word adversary (ies) to denote all the forces that impede the progress of his/her own discipline.

In the Oxford dictionary (1976), the concepts of adversaries and enemies are considered synonyms. However other sources show a distinction between these two concepts.

An enemy is seen as a hated opponent and is usually considered a person who hates another and eagerly seeks his/her defeat. Words used in lieu of ‘enemy’ include: opponent; hostile army or nation, an alien.

An adversary is an opponent who is not hated; an adversary is someone who is ‘in front of, opposed, coming from another direction, averse…